activity river and invisible group bug 1.7

clean install of Elgg 1.7 on DELL1950III CentOS 5.4 PHP 5.2.10 (cli) Apache 2.2.3-22 MySQL 5.1.39 using base/remi/epel repos

invisible groups working perfect by create group then edit group and set group access to group name

PROBLEM:

the river activity displays to public (and all other user levels) the discussion of the invisible group (group icon, group name, discussion title, first few lines of the discussion text) betraying the invisible status of the group and breaking the privacy of the group

no 3rd party plugins installed. the error can be reproduced with out of the box 1.7 curverider plugins only